The public-choice school of economics, developed since the mid-20th century, assumes that an individual who moves from the private sector to the public sector, whether as a government bureaucrat or a politician, remains the same mostly self-interested individual. He does not metamorphose into an altruist angel. This view of "politics without romance" (to quote James Buchanan) led to new and fruitful explanations of government actions. We should expect that a president (or another top ruler) will, if not effectively constrained...